U.S. patent application number 13/096124 was filed with the patent office on 2012-11-01 for signaling to establish multipoint communications.
This patent application is currently assigned to Renesas Mobile Corporation. Invention is credited to Christopher Peter Callender, Keiichi Kubota, Brian Alexander Martin, Luis Miguel Santos Barreto.
Application Number | 20120276915 13/096124 |
Document ID | / |
Family ID | 47068265 |
Filed Date | 2012-11-01 |
United States Patent
Application |
20120276915 |
Kind Code |
A1 |
Kubota; Keiichi ; et
al. |
November 1, 2012 |
Signaling To Establish Multipoint Communications
Abstract
A user equipment UE sends to a network an indication that a
neighbor cell is suitable for data communications with the UE. The
UE is in a state with a serving cell in which no dedicated physical
channel is allocated to the UE. In response to the indication the
network and UE conduct multipoint communications between the UE and
the serving cell and the neighbor cell using a common channel
configuration the UE receives from at least one of the serving cell
and the neighbor cell. In a UTRAN embodiment the state is a
CELL-FACH state. Various embodiments details specific RRC messages
for various signaling, and in one embodiment there are different
procedures depending on whether the serving cell and the neighbor
cell belong to the same or different NodeB groups. Further
embodiments address when the neighbor cell is no longer suitable
for multipoint data communications with the UE.
Inventors: |
Kubota; Keiichi; (Weybridge,
GB) ; Martin; Brian Alexander; (Farnham, GB) ;
Santos Barreto; Luis Miguel; (Camberley, GB) ;
Callender; Christopher Peter; (Fleet, GB) |
Assignee: |
Renesas Mobile Corporation
|
Family ID: |
47068265 |
Appl. No.: |
13/096124 |
Filed: |
April 28, 2011 |
Current U.S.
Class: |
455/452.1 ;
455/422.1 |
Current CPC
Class: |
H04W 24/02 20130101;
H04B 7/024 20130101; H04W 72/0406 20130101 |
Class at
Publication: |
455/452.1 ;
455/422.1 |
International
Class: |
H04W 4/00 20090101
H04W004/00; H04W 72/04 20090101 H04W072/04 |
Claims
1. A method, comprising: receiving from a user equipment an
indication that a neighbor cell is suitable for data communications
with the user equipment, in which the user equipment is in a state
with a serving cell in which no dedicated physical channel is
allocated to the user equipment; and in response, coordinating for
the serving cell and the neighbor cell to conduct multipoint
communications with the user equipment.
2. The method according to claim 1, in which: the state is a
CELL-FACH state; the indication is received in a first Radio
Resource Control Measurement Report; and coordinating comprises
sending to the user equipment a Radio Resource Control message
which includes parameters for the multipoint communications between
the user equipment and the neighbor cell; in which the first Radio
Resource Control message comprises one of a Radio Bearer Setup,
Radio Bearer Reconfiguration, Radio Bearer Release, Physical
Channel Reconfiguration and a Transport Channel Reconfiguration
message.
3. The method according to claim 1, further comprising each of the
serving cell and the neighbor cell broadcasting in system
information an indication of which NodeB group they belong; in
which the coordinating is by a common NodeB for the case the
serving cell and the neighbor cell belong to the same NodeB group,
and the coordinating is by a radio network controller for the case
the serving cell and the neighbor cell belong to different NodeB
groups.
4. The method according to claim 1, further comprising sending to
the user equipment parameters for deciding when a given neighbor
cell is suitable for data communications with the user equipment
and for deciding when a given neighbor cell is no longer suitable
for ongoing data communications with the user equipment.
5. The method according to claim 1, further comprising: receiving
from the user equipment a further indication that the neighbor cell
is no longer suitable for data communications with the user
equipment; and in response discontinuing the multipoint
communications between the neighbor cell and the user
equipment.
6. The method according to claim 5, in which: the further
indication is received in a second Radio Resource Control
Measurement report message, and discontinuing the multipoint
communications comprises: sending to the user equipment a second
Radio Resource Control message which commands the release radio
resources allocated for the multipoint communications between the
neighbor cell and the user equipment, in which the second Radio
Resource Control message comprises one of a Radio Bearer Setup,
Radio Bearer Reconfiguration, Radio Bearer Release, Physical
Channel Reconfiguration or Transport Channel Reconfiguration
message; and in response receiving from the user equipment a third
Radio Resource Control message in which the third Radio Resource
Control message comprises one of a Radio Bearer Setup Complete,
Radio Bearer Reconfiguration Complete, Radio Bearer Release
Complete, Physical Channel Reconfiguration Complete or Transport
Channel Reconfiguration Complete message.
7. The method according to claim 1 executed by a wireless network,
in which the state is a CELL-FACH state; the method further
comprising: sending to the user equipment parameters by which to
determine whether a neighbor cell from data communications with the
user equipment; in at least one system information block,
broadcasting parameters for HS-DSCH reception in the CELL-FACH
state and an indication of which NodeB group the serving cell and
the neighbor cell belong; sending to the user equipment a neighbor
cell list which comprises the said neighbor cell; the received
indication comprises a first Radio Resource Control Measurement
report; for the case the serving cell and the neighbor cell belong
to the same NodeB group the coordinating is by a common NodeB and
for the case the serving cell and the neighbor cell belong to
different NodeB groups the coordinating is by a radio network
controller; receiving from the user equipment a second Radio
Resource Control Measurement report indicating that the neighbor
cell is no longer suitable for data communications; and in
response, discontinuing the multipoint communications between the
neighbor cell and the user equipment.
8. An apparatus comprising: at least one processor; and at least
one memory storing a computer program; in which the at least one
memory with the computer program is configured with the at least
one processor to cause the apparatus to at least: receive from a
user equipment an indication that a neighbor cell is suitable for
data communications with the user equipment, in which the user
equipment is in a state with a serving cell in which no dedicated
physical channel is allocated to the user equipment; and in
response, coordinate for the serving cell and the neighbor cell to
conduct multipoint communications with the user equipment.
9. The apparatus according to claim 8, in which: the state is a
CELL-FACH state; the indication is received in a first Radio
Resource Control Measurement Report; and coordinating comprises
sending to the user equipment a Radio Resource Control message
which includes parameters for the multipoint communications between
the user equipment and the neighbor cell; in which the first Radio
Resource Control message comprises one of a Radio Bearer Setup,
Radio Bearer Reconfiguration, Radio Bearer Release, Physical
Channel Reconfiguration and a Transport Channel Reconfiguration
message.
10. The apparatus according to claim 8, in which each of the
serving cell and the neighbor cell broadcast in system information
an indication of which NodeB group they belong; and in which the
coordinating is by a common NodeB for the case the serving cell and
the neighbor cell belong to the same NodeB group, and the
coordinating is by a radio network controller for the case the
serving cell and the neighbor cell belong to different NodeB
groups.
11. The apparatus according to claim 8, in which the at least one
memory with the computer program is configured with the at least
one processor to cause the apparatus to further send to the user
equipment parameters for deciding when a given neighbor cell is
suitable for data communications with the user equipment and for
deciding when a given neighbor cell is no longer suitable for
ongoing data communications with the user equipment.
12. The apparatus according to claim 8, in which the at least one
memory with the computer program is configured with the at least
one processor to cause the apparatus to further: receive from the
user equipment a further indication that the neighbor cell is no
longer suitable for data communications with the user equipment;
and in response discontinue the multipoint communications between
the neighbor cell and the user equipment.
13. The apparatus according to claim 12, in which: the further
indication is received in a second Radio Resource Control
Measurement report message, and the apparatus is configured to
discontinue the multipoint communications by: sending to the user
equipment a second Radio Resource Control message which commands
the release radio resources allocated for the multipoint
communications between the neighbor cell and the user equipment, in
which the second Radio Resource Control message comprises one of a
Radio Bearer Setup, Radio Bearer Reconfiguration, Radio Bearer
Release, Physical Channel Reconfiguration or Transport Channel
Reconfiguration message; and in response receiving from the user
equipment a third Radio Resource Control message in which the third
Radio Resource Control message comprises one of a Radio Bearer
Setup Complete, Radio Bearer Reconfiguration Complete, Radio Bearer
Release Complete, Physical Channel Reconfiguration Complete or
Transport Channel Reconfiguration Complete message.
14. The apparatus according to claim 8, in which the apparatus
comprises a wireless network node, and the state is a CELL-FACH
state; and the at least one memory with the computer program is
configured with the at least one processor to cause the apparatus
to further: send to the user equipment parameters by which to
determine whether a neighbor cell from data communications with the
user equipment; broadcast in at least one system information block
parameters for HS-DSCH reception in the CELL-FACH state and an
indication of which NodeB group the serving cell and the neighbor
cell belong; send to the user equipment a neighbor cell list which
comprises the said neighbor cell; the received indication comprises
a first Radio Resource Control Measurement report; for the case the
serving cell and the neighbor cell belong to the same NodeB group
the coordinating is by a common NodeB and for the case the serving
cell and the neighbor cell belong to different NodeB groups the
coordinating is by a radio network controller; receive from the
user equipment a second Radio Resource Control Measurement report
indicating that the neighbor cell is no longer suitable for data
communications; and in response. discontinue the multipoint
communications between the neighbor cell and the user
equipment.
15. A computer readable memory storing a computer program which
when executed by at least one processor results in actions
comprising: receiving from a user equipment an indication that a
neighbor cell is suitable for data communications with the user
equipment, in which the user equipment is in a state with a serving
cell in which no dedicated physical channel is allocated to the
user equipment; and in response, coordinating for the serving cell
and the neighbor cell to conduct multipoint communications with the
user equipment.
16. The computer readable memory according to claim 15, in which:
the state is a CELL-FACH state; the indication is received in a
first Radio Resource Control Measurement Report; and coordinating
comprises sending to the user equipment a Radio Resource Control
message which includes parameters for the multipoint communications
between the user equipment and the neighbor cell; in which the
first Radio Resource Control message comprises one of a Radio
Bearer Setup, Radio Bearer Reconfiguration, Radio Bearer Release,
Physical Channel Reconfiguration and a Transport Channel
Reconfiguration message.
17. The computer readable memory according to claim 15, the actions
further comprising each of the serving cell and the neighbor cell
broadcasting in system information an indication of which NodeB
group they belong; in which the coordinating is by a common NodeB
for the case the serving cell and the neighbor cell belong to the
same NodeB group, and the coordinating is by a radio network
controller for the case the serving cell and the neighbor cell
belong to different NodeB groups.
18. The computer readable memory according to claim 15, the actions
further comprising sending to the user equipment parameters for
deciding when a given neighbor cell is suitable for data
communications with the user equipment and for deciding when a
given neighbor cell is no longer suitable for ongoing data
communications with the user equipment.
19. The computer readable memory according to claim 15, the actions
further comprising: receiving from the user equipment a further
indication that the neighbor cell is no longer suitable for data
communications with the user equipment; and in response
discontinuing the multipoint communications between the neighbor
cell and the user equipment.
20. The computer readable memory according to claim 19, in which:
the further indication is received in a second Radio Resource
Control Measurement report message, and discontinuing the
multipoint communications comprises: sending to the user equipment
a second Radio Resource Control message which commands the release
radio resources allocated for the multipoint communications between
the neighbor cell and the user equipment, in which the second Radio
Resource Control message comprises one of a Radio Bearer Setup,
Radio Bearer Reconfiguration, Radio Bearer Release, Physical
Channel Reconfiguration or Transport Channel Reconfiguration
message; and in response receiving from the user equipment a third
Radio Resource Control message in which the third Radio Resource
Control message comprises one of a Radio Bearer Setup Complete,
Radio Bearer Reconfiguration Complete, Radio Bearer Release
Complete, Physical Channel Reconfiguration Complete or Transport
Channel Reconfiguration Complete message.
21.-40. (canceled)
Description
TECHNICAL FIELD
[0001] The exemplary and non-limiting embodiments of this invention
relate generally to wireless communication systems, methods,
devices and computer programs and, more specifically, relate to
signaling in support of and network coordination for multipoint
communications between a network and a user equipment.
BACKGROUND
[0002] The following abbreviations that may be found in the
specification and/or the drawing figures are defined as
follows:
[0003] 3GPP third generation partnership project
[0004] DL downlink (network towards UE)
[0005] E-DCH enhanced dedicated (physical) channel
[0006] E-DPCCH enhanced dedicated physical control channel
[0007] E-DPDCH enhanced dedicated physical data channel
[0008] E-HICH E-DCH HARQ acknowledgement indicator channel
[0009] E-RGCH E-DCH relative grant channel
[0010] E-RNTI E-DCH radio network temporary identifier
[0011] FACH forward access channel
[0012] HARQ hybrid automatic repeat request
[0013] H-RNTI HS-DSCH radio network temporary identifier
[0014] HSPDA high speed downlink packet access
[0015] HS-DSCH high speed downlink shared channel
[0016] HS-DPCCH high speed dedicated physical control channel
[0017] IE information element
[0018] NCL neighbor cell list
[0019] Node B base station
[0020] RF radio frequency
[0021] RNC radio network controller
[0022] RRC radio resource control
[0023] SI system information
[0024] SIB system information block
[0025] UE user equipment
[0026] UL uplink (UE towards network)
[0027] UTRAN universal terrestrial radio access network
[0028] Continuing improvements of the UTRAN system have recently
included the investigation of a CELL-FACH enhancement which in part
intends to improve cell reselection. A UE in the CELL-FACH state
has no dedicated physical channel allocated to it, but instead it
continuously monitors the FACH in the DL and is assigned a random
access channel RACH for accessing an uplink transport channel.
While in the CELL-FACH state the UE can have only one serving cell,
and so it performs cell reselection according to specified
reselection rules, typically to change the current serving cell to
a better quality neighbor cell.
[0029] In current specifications the UE does this by first
obtaining the system information of the neighbor cell (typically
1.28 seconds) then sends a cell update message upon cell
reselection while in the in CELL-FACH state so that the network can
provide a dedicated resource on the new serving cell for the UE.
The network provides this resource in a Cell Update Confirm
message, and the cell update procedure can take up to a full second
to perform. These conventional procedures are detailed at 3GPP TS
25.331 v10.3.1 (2011 April) subclause 8.3.1. But until this cell
update procedure is complete, the UE cannot perform user data
transmission and reception and so there is a time, on the order of
up to a few seconds, during which service is disrupted due to the
cell reselection.
[0030] Also, in Release-8 of UTRAN there was introduced an
"Enhanced Uplink in CELL-FACH state and idle mode" feature, by
which the UE cannot perform cell reselection when it has an uplink
resource allocated to it by the network. So a UE capable of this
enhanced uplink in CELL-FACH state and idle mode is at risk of
losing its synchronization to its serving cell due to that cell
reselection restriction. It is expected that the CELL-FACH
enhancement noted above will address this particular issue (e.g.,
in 3GPP Release 11) by allowing reselection during an ongoing E-DCH
transmission. But still some improvements are required to enable
this while avoiding or minimizing other problems.
[0031] Finally, another problem arises where the UE's reception of
both the serving cell and the detected neighbor cells are all
relatively weak. In this case reception on only a single cell would
be unreliable, and potentially under some fading conditions the UE
may reselect back and forth between difference cells in a kind of
ping-pong effect as a result of poor signal reception which is only
transient at the UE. Reception from multiple cells simultaneously
would increase the reliability since the UE could then combine the
successful reception from different cells. On balance this could
potentially reduce the uplink signaling load since the UE would
engage in fewer total reselections and corresponding cell update
procedures.
[0032] Exemplary embodiments detailed below with particularity
provide solutions to the above problems in that they detail UE and
network actions for multipoint reception at the UE in the CELL-FACH
state from multiple network cells. While it is possible that the UE
could autonomously find all the network cells it needs for
multipoint communications and the network could `blindly` schedule
on all the possible cells to that UE, this uncoordinated approach
would result in wasted radio resources. Thus the exemplary
embodiments include control signaling for making the multipoint
communications both more targeted and more efficient from the
perspective of total radio resources used perspective.
SUMMARY
[0033] The foregoing and other problems are overcome, and other
advantages are realized, by the use of the exemplary embodiments of
this invention.
[0034] In a first exemplary embodiment of the invention there is a
method comprising: receiving from a user equipment an indication
that a neighbor cell is suitable for data communications with the
user equipment; and in response coordinating for the serving cell
and the neighbor cell to conduct multipoint communications with the
user equipment. In this embodiment the user equipment is in a state
with a serving cell in which no dedicated physical channel is
allocated to the user equipment.
[0035] In a second exemplary embodiment of the invention there is
an apparatus comprising at least one processor and at least one
memory storing a computer program. In this embodiment the at least
one memory with the computer program is configured with the at
least one processor to cause the apparatus to at least receive from
a user equipment an indication that a neighbor cell is suitable for
data communications with the user equipment, in which the user
equipment is in a state with a serving cell in which no dedicated
physical channel is allocated to the user equipment; and in
response, coordinate for the serving cell and the neighbor cell to
conduct multipoint communications with the user equipment
[0036] In a third exemplary embodiment of the invention there is a
computer readable memory storing a computer program which when
executed by at least one processor results in actions comprising:
receiving from a user equipment an indication that a neighbor cell
is suitable for data communications with the user equipment, in
which the user equipment is in a state with a serving cell in which
no dedicated physical channel is allocated to the user equipment;
and in response, coordinating for the serving cell and the neighbor
cell to conduct multipoint communications with the user
equipment.
[0037] In a fourth exemplary embodiment of the invention there is a
method comprising: sending from a user equipment an indication that
a neighbor cell is suitable for data communications with the user
equipment; and in response conducting multipoint communications
with the serving cell and the neighbor cell using a common channel
configuration received from at least one of the serving cell and
the neighbor cell. In this embodiment also the user equipment is in
a state with a serving cell in which no dedicated physical channel
is allocated to the user equipment.
[0038] In a fifth exemplary embodiment of the invention there is an
apparatus comprising at least one processor and at least one memory
storing a computer program. In this embodiment the at least one
memory with the computer program is configured with the at least
one processor to cause the apparatus to at least send from a user
equipment an indication that a neighbor cell is suitable for data
communications with the user equipment, in which the user equipment
is in a state with a serving cell in which no dedicated physical
channel is allocated to the user equipment; and in response,
conduct multipoint communications with the serving cell and the
neighbor cell using a common channel configuration received from at
least one of the serving cell and the neighbor cell.
[0039] In a sixth exemplary embodiment of the invention there is a
computer readable memory storing a computer program which when
executed by at least one apparatus results in actions comprising:
sending from a user equipment an indication that a neighbor cell is
suitable for data communications with the user equipment, in which
the user equipment is in a state with a serving cell in which no
dedicated physical channel is allocated to the user equipment; and
in response, conducting multipoint communications with the serving
cell and the neighbor cell using a common channel configuration
received from at least one of the serving cell and the neighbor
cell.
[0040] By example the first through third exemplary embodiments
above are from the network's perspective while the fourth through
sixth exemplary embodiments are from the UE's perspective. These
and other embodiments and aspects are detailed below with
particularity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] FIG. 1 is a schematic diagram of adjacent NodeBs with a UE
moving amongst their cells and is an environment in which
embodiments of the invention may be advantageously practiced.
[0042] FIG. 2A is a signaling diagram illustrating processes for
establishing multipoint communications between two network cells
and a UE according to an exemplary embodiment of the invention.
[0043] FIG. 2B is a signaling diagram illustrating processes for
discontinuing the multipoint communications first established at
FIG. 2A according to an exemplary embodiment of the invention.
[0044] FIG. 3A is a signaling diagram similar to FIG. 2A but
illustrating alternative processes for establishing multipoint
communications between two network cells and a UE according to an
exemplary embodiment of the invention.
[0045] FIG. 3B is a signaling diagram illustrating alternative
processes for discontinuing the multipoint communications first
established at FIG. 3A according to an exemplary embodiment of the
invention.
[0046] FIGS. 4A-B are logic flow diagrams that illustrates the
operation of a method, and a result of execution of computer
program instructions embodied on a computer readable memory, in
accordance with the exemplary embodiments of this invention.
[0047] FIG. 5 is a simplified block diagram of the UE and a NodeB
from FIG. 1 and also a higher network node, which are exemplary
electronic devices suitable for use in practicing the exemplary
embodiments of this invention.
DETAILED DESCRIPTION
[0048] Consider FIG. 1 which illustrates an exemplary environment
in which exemplary embodiments of the invention may be practiced to
advantage. There is a UE in a CELL-FACH state and under control of
a serving cell denoted as cell1. The UE is moving towards two
neighbor cells, cell2 and cell3. Cell2 is in the same NodeB-1 group
as the serving cell1, while cell3 is in a different NodeB-2 group.
Conventionally the geographic area controlled by a NodeB is served
by directional antennas. Each NodeB may control several cells,
typically arranged in different sectors (e.g., three or six sector
sites). While Cell1 and Cell2 may be considered from the network
perspective different sectors of the same NodeB cell, since each
sector has a different physical configuration the UE sees each
sector as a different cell. Similarly, if a NodeB also has relay
nodes and/or remote radio heads, the UE will also see those as
separate cells rather than distinct sectors under a given NodeB's
control. The description below uses the term cell in reference to
the network access node which controls a sector (or which controls
an entire NodeB geographic area if there are no sector
divisions).
[0049] The exemplary embodiments of the invention below are
described in the initial context of the UE in the Cell-FACH state
moving away from its serving cell towards neighbor cell2 and
neighbor cell3 so that the UE's received signal strength from cell
is diminishing while that from cell2 and cell3 is increasing. While
these examples are also in the context of the UTRAN system and
specifically HSDPA, such context is for clarity of description and
is not itself a limit; these teachings may be employed in that and
in other radio access technologies such as evolved UTRAN, WCDMA and
others.
[0050] In the following signaling diagrams, FIG. 2A illustrates a
first exemplary embodiment for establishing multipoint
communications between two network cells (serving cell and neighbor
cell2 and/or neighbor cell3) and a UE according, and FIG. 2B
illustrates a first exemplary embodiment for discontinuing the
multipoint communications first established at FIG. 2A.
Respectively, FIGS. 3A and 3B illustrate similarly for a second
exemplary embodiment. Within FIGS. 2B and 3B are two options for
how the neighbor cell radio resources for the multipoint
communications are released; by explicit signaling and implicit
within other signaling. These examples are operative for UL
transmissions by the UE and multipoint reception at the network
nodes/cells, for DL multipoint transmissions by the network
nodes/cells for reception at the UE, and for both UL and DL. Each
of these are encompassed by the more generic term multipoint
communications, in which the UE uses more than one serving HS-DSCH
cell in the CELL-FACH state for downlink data reception (multipoint
HSDPA operation in CELL-FACH) or uplink data transmission.
[0051] Now consider the first embodiment at FIG. 2A for
establishing multipoint communications. For the multipoint HSDPA
operation in CELL-FACH state 204, the serving cell 22 transmits and
the UE 20 receives at 202 an information element IE indicating to
what NodeB group the serving cell 22 belongs so that the UE can
identify whether or not some other neighbor cell the UE later
measures belongs to the same or different NodeB as the current
serving cell 22. By example the NodeB group may be indicated by an
index number of NodeB groups. In further portions of FIG. 2A, the
first neighbor cell 26 is within the same NodeB group as the
serving cell 22 and the second neighbor cell 28 is in a different
NodeB group. As well as indicating the grouping of the serving cell
22, in an exemplary embodiment the serving cell 22 may also
indicate the grouping of neighbor cells in the neighbor cell list
which the serving cell 22 signals to the UE 20. Alternative to
signaling the NodeB group indication in the IE, the serving cell 22
may broadcast that information in system information.
[0052] The UE 20 either sees its received signal strength or
quality from the serving cell 20 dropping, or it sees its received
signal strength or quality from the neighbor cell 26 increasing or
anticipates that it eventually will and so the UE 20 obtains the
common channel configuration parameters 206 for its communications
with the neighbor cell 26. In one embodiment the UE 20 obtains this
from system information 208 broadcast by the neighbor cell 26, or
alternatively from a dedicated message sent by the serving cell 22.
In a UTRAN specific implementation, the network signals the
parameters 206 for HS-DSCH reception while the UE 20 is in the
CELL-FACH state in SIB5, and the IE indicating to what NodeB group
the cell belongs is also broadcast in SIB5. The UE can know which
neighbor cells to measure from a neighbor cell list the UE 20
receives from the network (serving cell 22).
[0053] In any case, the UE 20 does receive the SI from the neighbor
cell 26 which carries an index or other identifier of which NodeB
group that neighbor cell 26 belongs. If the neighbor cell 26
belongs to the same NodeB group as the serving cell 22 as will be
first detailed then the UE 20 facilitates multipoint communications
with the serving cell 22 and the same-NodeB group neighbor cell 26
according to a first procedure, else if the neighbor cell 28
belongs to a different NodeB group than the serving cell 22 as will
be next detailed then the UE 20 facilitates multipoint
communications with the serving cell 22 and the different-NodeB
group neighbor cell 28 according to a second procedure. This is not
mutually exclusive; the UE 20 may choose to facilitate multipoint
communications with the serving cell 22, the same-NodeB group
neighbor cell 26, and the different-NodeB group neighbor cell 28 by
utilizing both first and second procedures.
[0054] The UE 20 identifies the neighbor cell 26 as belonging to
the same NodeB group as the serving cell 22 at block 210, and so
will undertake the first procedure. Based on the UE's measurement
of that neighbor cell 26 it sends UL signaling 212 to the serving
cell 22 indicating that neighbor cell 26 is useable for data
reception and/or transmission to/from the UE 20. This UL signaling
may for the first procedure be via a UL physical channel and for
the second procedure be via an RRC message.
[0055] Still in the first procedure, the network then starts
multipoint communications 214 over the serving cell and the
same-NodeB group neighbor cell 26 in response to that UL signaling
212. In a specific embodiment for UTRAN, this multipoint
communication 214 is HS-DSCH transmission and/or common E-DCH
reception over the serving cell 20 and the reported 212 neighbor
cell 26; and the UE 20 starts HS-DSCH reception and/or common E-DCH
transmission over the serving cell 20 and the reported 212 neighbor
cell 26 (or neighbor cells if more than one neighbor cell joins the
serving cell 22 in the multipoint communications). Note that the
HS-DSCH data 214 of FIG. 2A is sent by or received at both the
serving cell 22 and the same-NodeB group neighbor cell 26.
[0056] Further portions of FIG. 2A illustrate the second procedure,
in which the neighbor cell 28 is a different-NodeB group than the
serving cell 22. The UE 20 obtains the common channel configuration
parameters 216 for its communications with the neighbor cell 28,
either from system information 218 broadcasted by the
different-NodeB group neighbor cell 28 or alternatively from a
dedicated message sent by the serving cell 22. The UE 20 identifies
at block 220 that the neighbor cell 28 belongs to a different NodeB
group than the serving cell 22, and so will undertake the second
procedure. Based on the UE's measurement of that neighbor cell 28
it sends UL signaling 222 to the RNC 24 indicating that this
neighbor cell 28 is useable for data reception and/or transmission
to/from the UE 20. As noted above, for the second procedure this UL
signaling 222 is an UL RRC message. In one embodiment this RRC
message 222 has an explicit indication that the neighbor cell 28 is
useable, and in another embodiment the RRC message 222 is a
measurement report which implicitly informs the RNC 24 that this
neighbor cell 28 is useable for multipoint communications.
[0057] Further in the second procedure, the network (e.g., the RNC
24 via the serving cell 22) responds with DL signaling 224 to
confirm the UL signaling 222 the uplink signaling, and in certain
exemplary embodiments this DL response signaling 224 is a RRC
message (e.g., Radio Bearer Reconfiguration message) which provides
to the UE 20 parameters for the multipoint communications (if some
or all were not received at block 216) and also additional
parameters which the UE 20 is to use with that different-NodeB
neighbor cell 28. Specific to UTRAN, these parameters may include
the H-RNTI for multipoint HS-DSCH reception operation and/or
Primary E-RNTI, Secondary E-RNTI, E-RGCH, E-HICH for E-DCH for
multipoint E-DCH transmission operation.
[0058] Now having the radio bearer and H-RNTI for the
different-NodeB group neighbor cell 28, the UE 20 then at block 226
starts to monitor the common channels for data reception, and sends
a UL RRC message 228 to the RNC 24 which for a UTRAN implementation
may be a Radio Bearer Reconfiguration Complete message (or
alternatively Radio Bearer Setup, Radio Bearer Release, Physical
Channel Reconfiguration, or Transport Channel Reconfiguration
message). The network then starts multipoint communications over
the serving cell and the different-NodeB group neighbor cell 28 in
response to that UL signaling 228 (e.g. Radio Bearer Setup
Complete, Radio Bearer Reconfiguration Complete, Radio Bearer
Release Complete, Physical Channel Reconfiguration Complete, or
Transport Channel Reconfiguration Complete message). In this case
though, if the multipoint communications are DL the RNC 24 sends
the DL data to both the serving cell 22 and the different-NodeB
group neighbor cell 28 as shown via messages 232 and 234, and the
wireless multipoint transmission to the UE 20 from those cells 22,
28 is via the HS-DSCH data messages 233 and 236 respectively. For
the first procedure both serving cell 22 and same-NodeB group
neighbor cell 26 received the data from the NodeB (but note that
either cell 22, 26 may itself be the NodeB). As with the first
procedure above, in a specific embodiment for UTRAN this multipoint
communication 233 236 may also be common E-DCH reception at the
serving cell 20 and the reported 222 neighbor cell 28.
[0059] FIG. 2B continues chronologically from FIG. 2A and
illustrates a first exemplary embodiment for discontinuing the
multipoint communications 240 established there using the
same-NodeB group neighbor cell 26 and the different-NodeB group
neighbor cell 28. At some point the UE 20 determines at block 242
that the same-NodeB group neighbor cell 26 is either no longer
reliable or soon will be, typically but not exclusively due to
diminished signal strength the UE 20 receives from it. The UE 20
decides as block 246 to stop the multipoint communications with the
same-NodeB group neighbor cell 26 and sends UL signaling 248 to the
serving cell 22 that the used neighbor cell 26 is no longer useable
for DL data reception and/or UL data transmission. In response the
network node coordinating the multipoint communications from the
network side (the NodeB in this case) simply discontinues sending
the UE's DL data to that neighbor cell 26 and/or discontinues
informing that neighbor cell 26 of the UL resources to monitor on
which the UE 20 is scheduled to send its UL data. Or the network
node coordinating the multipoint communications can explicitly
release the neighbor cell 26 from multipoint communications with
that specific UE 20. In this case both the serving cell 22 and the
neighbor cell 26 are in the same NodeB group and so the node
coordinating the multipoint communications will typically be the
NodeB. At block 250 the same-NodeB group neighbor cell 26 then
stops its transmission to and/or reception from the UE 20.
[0060] Further portions of FIG. 2B are directed to the case in
which the neighbor cell 28 participating in the multipoint
communications 240 is a different-NodeB group than the serving cell
22. Two options are shown, explicit and implicit release of the
different-NodeB group neighbor node 28 radio resources. In either
case, as with FIG. 2A it may be considered that the UE 20 follows a
first procedure for dropping a neighbor cell 26 from multipoint
communications (which may or may not terminate the multipoint
communications, depending on whether one or more neighbor cells are
participating) if the neighbor cell 26 is a same-NodeB group as the
serving cell 22, and follows a second procedure for dropping a
neighbor cell 28 from multipoint communications if the neighbor
cell 28 is a different-NodeB group from the serving cell 22. Both
the explicit and the implicit release described below are
embodiments of this second procedure. Both releases begin with the
UE 20 determining at block 252 that the different-NodeB group
neighbor cell 28 is no longer reliable (or soon will be) for data
communications and decides at that block to stop the multipoint
communications with it.
[0061] For the explicit release of different-NodeB group neighbor
cell 28 radio resources, the UE 20 sends a UL message 254A to the
RNC 24 which by example is a RRC message (e.g., measurement report)
which informs explicitly or implicitly that the different-NodeB
group neighbor cell 28 is no longer useable for DL data reception
and/or UL data transmission. In response the RNC 24 sends in
response to message 254A a DL RRC message 256A which commands
removal of resources allocated for that different-NodeB group
neighbor cell 28. By example, in a UTRAN implementation this may be
a Physical Channel Reconfiguration message (or alternatively Radio
Bearer Setup, Radio Bearer Reconfiguration, Radio Bearer Release,
or Transport Channel Reconfiguration message). At block 258A the UE
20 stops multipoint communications with the different-NodeB group
neighbor cell 28 and releases the resources commanded in message
256A, then sends to the RNC 24 an UL RRC message 260A confirming
its actions at block 258A. In a UTRAN implementation this UL RRC
message 260A is by example a Physical Channel Reconfiguration
Complete message (or alternatively Radio Bearer Setup Complete,
Radio Bearer Reconfiguration Complete, Radio Bearer Release
Complete or Transport Channel Reconfiguration Complete
message).
[0062] For the implicit release of different-NodeB group neighbor
cell 28 radio resources, the UE 20 at block 258B simply stops
multipoint communications with the different-NodeB group neighbor
cell 28 and releases the radio resources it uses with that
different-NodeB group neighbor cell 28 for the multipoint
communications 240, and then sends to the RNC 24 an UL RRC message
260B which implicitly confirm its actions at block 258B. In a UTRAN
implementation this UL RRC message 260B is by example a measurement
report.
[0063] In summary, one possible UTRAN specific implementation of
this first embodiment is as follows. The network signals the
parameters for HS-DSCH reception in CELL-FACH state feature in SIB5
or SIB5bis, and optionally in that SIB5 or SIB5bis also signals the
IE which indicates to what NodeB group the cell belongs. The UE 20
finds the neighbor cell SI broadcasts because it measures neighbor
cells in a neighbor cell list provided by the network. For the
first procedure the UE 20 starts receiving HS-DSCH over the current
serving cell 22 and the same-NodeB group neighbor cell 26 and
reports to the NodeB about the use of the neighbor cell via uplink
physical channel such as HS-DPCCH, E-DPCCH or E-DPDCH. The NodeB
then starts sending downlink data over the same-NodeB group
neighbor cell 26 after the reception of the report from UE 20. For
the second procedure the UE 20 starts receiving HS-DSCH over the
current serving cell 22 and the different-NodeB group neighbor cell
28 and reports to the RNC 24 about the use of the neighbor cell 28
via an uplink RRC message (e.g. measurement report).
[0064] Alternatively, instead of first and second procedures the UE
20 can use the second procedure for any neighbor cell.
Specifically, the UE 20 starts receiving HS-DSCH over the current
serving cell 22 and the some neighbor cell 26, 28 regardless of the
associated NodeB group and reports to the RNC 24 about the use of
the neighbor cell 26, 28 via an uplink RRC message (e.g.
measurement report). The network then starts sending downlink data
over the neighbor cell 26, 28 after the reception of the uplink RRC
message.
[0065] For discontinuing a cell from the multipoint communication,
the UE reports to the network via an uplink RRC message (e.g.
measurement report) that the used neighbor cell 26, 28 is no longer
useable (or no longer being used by the UE 20) for the downlink
data reception and/or transmission when the used neighbor cell 26,
28 becomes too weak to continue the downlink data reception and/or
transmission. Then the network stops sending downlink data over the
non-used neighbor cell 26, 28 after the reception of that uplink
RRC message.
[0066] The second exemplary embodiment noted above is shown in the
signaling diagrams of FIGS. 3A-B. For establishing a neighbor cell
in multipoint communications at FIG. 3A, the UE 20 is in a
CELL-FACH state 304 and the UE 20 gets 306 the parameters for
HS-DSCH reception in the CELL-FACH state in SIB5 or SIB5bis of the
respective cell's 22, 26 broadcast SI. The UE 20 measures the
neighbor cells in a neighbor cell list provided by the
network/serving cell 22 and reports the measured neighbor cells to
the network/RNC 24 (or at least those which are useable for HSDPA
and/or UL data transmission) via an uplink RRC message 322A (e.g.
measurement report). In this embodiment the network may decide
based on the measurement report 322A that neighbor cell 26 is
useable for multipoint communications with the UE 20 (the network
will know the UE's capability for multipoint communications from UE
capabilities reported during RRC connection establishment or a UE
capability information procedure, from contacting the UE's home
network or from the class rating the UE reports for itself).
[0067] The network (the RNC 24 via the serving cell 22) then sends
a downlink RRC message 324A. By example message 324A may for a
UTRAN implementation be a Radio Bearer Setup, Radio Bearer
Reconfiguration, Radio Bearer Release, Physical Channel
Reconfiguration, or Transport Channel Reconfiguration message. This
message 324A provides to the UE 20 the configuration parameters for
the multipoint communications. For a UTRAN specific implementation,
these parameters may be H-RNTI for HS-DSCH reception from and/or
Primary E-RNTI, Secondary E-RNTI, E-RGCH, E-HICH for E-DCH for
common E-DCH transmission to the neighbor cell 26.
[0068] The UE 20 starts at block 326A the multipoint communications
(HS-DSCH reception and/or common E-DCH transmission) which now
include the newly added neighbor cell 26 and sends a reply message
328A to message 324A. By example this reply RRC message 328A may be
a UL Radio Bearer Setup Complete, Radio Bearer Reconfiguration
Complete, Radio Bearer Release Complete, Physical Channel
Reconfiguration Complete, or Transport Channel Reconfiguration
Complete message. The RNC 24 in response to receiving this UL
message 328A then begins, for the case of DL multipoint
communications, to send DL data 334A addressed to the UE 20 to the
newly added neighbor cell 26 as well as to the serving cell 22, and
both the newly added neighbor cell 26 and the serving cell 22
transmit this HS-DSCH data 336A to the UE in multipoint fashion.
While FIG. 3-A only illustrates DL multipoint communication 336A,
for UTRAN this multipoint communication may be implemented in the
UL direction as common E-DCH reception at the serving cell 20 and
the neighbor cell 26 reported at UL RRC message 322A.
[0069] For the case in which the neighbor cell 28 is not in the
same NodeB group as the serving cell 22 the procedure in this
second exemplary embodiment is much the same, since this embodiment
does not entail different procedures depending on what NodeB group
the neighbor cell belongs.
[0070] The UE 20 in the CELL-FACH state 304 gets from the network
at 316 the parameters for HS-DSCH reception in SIB5 or SIB5bis of
the respective cell's 22, 28 broadcast SI. The UE 20 measures
neighbor cell 28 and sends a measurement report 322B to the network
which indicates the neighbor cell 28 is useable for multipoint
communications. The network then sends a downlink RRC message 324B
(e.g., Radio Bearer Setup, Radio Bearer Reconfiguration, Radio
Bearer Release, Physical Channel Reconfiguration, or Transport
Channel Reconfiguration message) which provides to the UE 20 the
configuration parameters (H-RNTI, E-RNTI, etc.) for the multipoint
communications with that neighbor cell 28
[0071] At block 326B the UE 20 starts the multipoint communications
(HS-DSCH reception and/or common E-DCH transmission) and sends a
reply message 328B to the RNC 24 (e.g., Radio Bearer Setup
Complete, Radio Bearer Reconfiguration Complete, Radio Bearer
Release Complete, Physical Channel Reconfiguration Complete, or
Transport Channel Reconfiguration Complete message). The RNC 24 in
response to receiving this UL message 328B then begins, for the
case of DL multipoint communications, to send DL data addressed to
the UE 20 to the newly added neighbor cell 28 at message 334B as
well as to the serving cell 22 at message 330B. Both the newly
added neighbor cell 28 and the serving cell 22 transmit this
HS-DSCH data 332B, 336B to the UE in multipoint fashion.
[0072] FIG. 3B continues chronologically from FIG. 3A and shows
signaling for when the neighbor cells 26, 28 are dropped from the
multipoint communications 340 according to the second exemplary
embodiment. The same procedure is used for either neighbor cell 26,
28, and so FIG. 3B describes the process for dropping neighbor cell
26. When the used neighbor cell 26 becomes at block 342 too weak to
continue the downlink data reception and/or transmission, for an
explicit release of radio resources the UE 20 reports to the
network via an uplink RRC message 354A (e.g. measurement report)
that the used neighbor cell 26 is no longer used for the downlink
data reception and/or transmission. The UE 20 then at block 358A
stops data reception and/or transmission over the no longer used
neighbor cell 26.
[0073] In one specific but non-limiting embodiment of this explicit
release, the network replies to the uplink RRC message 354A with a
DL RRC message 356A (e.g. Radio Bearer Setup, Radio Bearer
Reconfiguration, Radio Bearer Release, Physical Channel
Reconfiguration or Transport Channel Reconfiguration message)
commanding removal of the radio resources allocated to the neighbor
cell 26 for multipoint communications with this UE 20, which the UE
20 responds with a UL RRC message (e.g. Radio Bearer Setup
Complete, Radio Bearer Reconfiguration Complete, Radio Bearer
Release Complete, Physical Channel Reconfiguration Complete or
Transport Channel Reconfiguration Complete message) 360A. Block
358A has the UE stopping data reception and/or transmission over
the neighbor cell 26 which is identified in the DL RRC message 356A
and releasing the radio resources commanded there prior to
signaling the UL confirmation RRC message 360A. In a different
specific but non-limiting embodiment of this explicit release the
UE 20 may release the resources allocated for the no longer used
neighbor cell 26 after transmitting its uplink RRC message (e.g.
measurement report) 354A. In either case, for the DL direction the
network stops sending downlink data over the non-used neighbor cell
26 after it receives the uplink RRC message 354A.
[0074] For an implicit release of radio resources the UE 20 at
block 358B stops data reception and/or transmission over the
neighbor cell 26 which the UE 20 determined at block 342 was too
weak to continue with multipoint communications 340, and sends an
UL RRC message 354B (e.g., measurement report) to the RNC 24
informing the network that this neighbor cell 26 is no longer
useable for multipoint communications and implicitly informing the
network that the radio resources allocated for multipoint
communications with this neighbor cell 26 are released/not being
used from the UE's perspective.
[0075] Whether the resource release is to be done via the implicit
or the explicit approach may be advantageously specified in a radio
access technology standard (e.g., 3GPP Release 11) so that both
network nodes and UEs will know which signaling protocol to use
without having to coordinate the decision via control
signaling.
[0076] One technical effect of the above procedures is that the UE
can receive downlink data via using more than one HS-DSCH serving
cell so data reception reliability is improved, particularly when
the UE is located at the cell edge. Another technical effect is
that for common E-DCH operation, the neighbor cell can control its
E-DCH transmission power via using the E-RGCH so it can reduce the
interference on its neighbor cells due to the common E-DCH
operation on the current serving cell.
[0077] The description of FIG. 2A provides that the UE 20 decides
whether a neighbor cell 26, 28 is suitable for inclusion in its
multipoint communications (whether it is suitable for reception by
the UE 20 of the HS-DSCH). The UE 20 can also make this decision
for the FIG. 3A implementation. At FIG. 2A the UE 20 decodes the SI
208, 218 of the neighbor cell 26, 28.
[0078] Below are detailed various criteria by which the UE 20 can
use to determine whether it should attempt to decode that neighbor
cell's SI in order to obtain the configuration that can be added to
its list of available cells for multipoint communications. Such
criteria may also be used by the UE 20 to determine when a
previously suitable cell 26, 28 should no longer be considered
suitable and hence should be removed from ongoing multipoint
communications with that UE 20. These criteria may be used
individually or in any combination.
[0079] A first criterion is for the UE 20 to use an absolute or
relative threshold which must be met for the measured neighbor cell
to be considered suitable or no longer suitable. If the cell meets
the threshold, then if it is not yet included in multipoint
communications the UE 20 should attempt to acquire its SI and if it
is acquired the cell is added to the list of available cells. If
the cell drops below the threshold then the cell is removed from
the list of available cells.
[0080] A second criterion modifies the first criteria above in that
a "time to trigger" is added. To prevent changing signal strength
in fading channel conditions from causing a cell to be added to and
dropped from the list, the absolute or relative threshold must be
met for some non-negligible time interval, for example one second.
In addition, hysteresis (lagging effect or path dependence) and
cell individual offsets can be added to the above thresholds for
determining when the UE autonomously attempts to acquire the SI and
when it decides a cell can be dropped from ongoing multipoint
communications. The specific values for when to attempt to acquire
the SI and when to attempt to drop may differ even though the
criteria concepts are the same (e.g., "leaving conditions" versus
"entering conditions").
[0081] A third criterion for the UE 20 may be used in addition to
the two above; the UE 20 informs the network (212 and 222 of FIG.
2A; 322A and 322B of FIG. 3A) that a neighbor cell is suitable for
multipoint communications only once the UE 20 has synchronized to
that cell's downlink common HS-DSCH. Similarly, any time the UE
detects on that channel that it is out of synchronization with that
cell then the UE 20 decides to drop that cell from multipoint
communications. For the latter case the drop decision is made
regardless of any other criteria.
[0082] A fourth criterion is that the UE 20 uses an absolute or
relative threshold which applies for the measured serving cell 22.
In this case the UE stops HS-DSCH reception from the neighbor
cell(s) 26, 28 if the serving cell signal quality is above or equal
to the threshold, and starts HS-DSCH reception from the neighbor
cell(s) if the serving cell 22 signal quality is below the
threshold.
[0083] In addition to those listed above, the UE 20 may also
consider its power supply status for determining whether starting
or stopping HS-DSCH reception from some cell other than the serving
cell. In this manner the UE 20 may avoid or reduce battery drain
due to the multipoint HSDPA reception. Any or all of the above
criteria may be used by the UE 20 to autonomously decide to add or
drop a neighbor cell from its list of suitable candidate cells for
multipoint communications.
[0084] In one embodiment, the serving cell 22 signals to the UE 20
its ability to perform multipoint communications in the CELL-FACH
state, and also the relevant criteria parameters for adding and/or
removing cells from the UE's list of suitable candidates for
multipoint communications. Cell specific information could be
either transmitted from the serving cell 22, or obtained from the
individual neighbor cells 26, 28 after SI acquisition (but at least
SI acquisition criteria needs to be signaled from the serving cell
22). In an alternate embodiment the network signals in the UE's
reconfiguration to the CELL-FACH state, transmitted on the serving
cell 22, the ability to perform multipoint transmission in
CELL-FACH state and also the relevant criteria parameters for
adding/removing neighbor cells from the UE's candidate list. In
still another alternative embodiment the parameters are fixed
(e.g., published in a wireless standard) and so need not be
signaled.
[0085] In practice, it is expected the UE 20 will start monitoring
the relevant neighbor cells (in any state) and build/maintain a
list of suitable cells based on the criteria for addition/removal,
and obtain the neighbor cell's system information if necessary.
Then once the UE 20 enters the CELL-FACH state, or when the list of
suitable cells changes based on the criteria, the UE 20 indicates
to the network the list of available cells. The UE 20 starts
HS-DSCH reception on the neighbor cell(s) using multipoint
communications (per FIG. 2A or 3A) if the given criteria are
met.
[0086] These add/drop criteria for the UE's candidate list exhibits
the following technical effects. Having specified rules for when
the UE 20 can consider a neighbor cell to be suitable results in
more predictable behavior from the network's perspective. For
implementations in which the parameters/criteria are signaled by
the network, this allows the network to control the criteria and
tailor it to different deployment scenarios. It also avoids failed
SI acquisition attempts, which result in reduced UE power
consumption. It also avoids the UE 20 adding a neighbor cell for
which it has obtained SI when that same recently added neighbor
cell does not provide sufficiently good reception of the HS-DSCH.
And additionally it avoids battery drain due to multipoint HSDPA
operation when the serving cell is strong enough to receive
downlink data reliably.
[0087] Now are detailed with reference to FIGS. 4A-B further
particular exemplary embodiments from the perspective of the
network (FIG. 4A) and the UE (FIG. 4B). At block 402 of FIG. 4A the
network receives from a UE an indication that a neighbor cell is
suitable for data communications with the UE. In this case the UE
is in a state with a serving cell of the network in which no
dedicated physical channel is allocated to the UE (e.g., CELL-FACH
state). In response to block 402, at block 404 the network
coordinates for the serving cell and the neighbor cell to conduct
multipoint communications with the UE.
[0088] From the UE's perspective at FIG. 4B, block 452 finds the UE
sending to the network an indication that a neighbor cell is
suitable for data communications with the UE. In this case also the
UE is in a state with a serving cell in which no dedicated physical
channel is allocated to the UE (e.g., CELL-FACH state). In response
to block 452, then at block 454 the UE conducts multipoint
communications with the serving cell and the neighbor cell using a
common channel configuration received from at least one of the
serving cell and the neighbor cell.
[0089] In the specific embodiments detailed above, the indication
of blocks 402 and 452 may be a measurement report with a list of
suitable candidate neighbor cells which the UE sends to the
network. Coordinating at block 404 may the network sending to the
UE a Radio Bearer Reconfiguration message (or alternatively Radio
Bearer Setup, Radio Bearer Release, Physical Channel
Reconfiguration or Transport Channel Reconfiguration message) which
includes parameters for the multipoint communications between the
user equipment and the neighbor cell. For the NodeB group specific
procedures, the serving cell and the neighbor cell broadcast in
their respective system information an indication of which NodeB
group they belong, and the coordinating of block 404 is then by a
common NodeB for the case the serving cell and the neighbor cell
belong to the same NodeB group, and the coordinating of block 404
is by a radio network controller for the case the serving cell and
the neighbor cell belong to different NodeB groups.
[0090] In the add/drop criteria described above in detail, the
network may further send to the UE parameters for deciding when a
given neighbor cell is suitable for data communications with the UE
and for deciding when a given neighbor cell is no longer suitable
for ongoing data communications with the UE; the add parameters may
or may not be the same as the drop parameters.
[0091] Once the neighbor cell is no longer suitable, the UE in an
embodiment sends a further or second indication (separate from the
indication of blocks 402 and 452) that the neighbor cell is no
longer suitable for data communications with the UE; and in
response the multipoint communications between the neighbor cell
and the user equipment are discontinued as variously shown at FIGS.
2B and 3B.
[0092] FIGS. 4A-B are logic flow diagrams which may be considered
to illustrate the operation of a method, and a result of execution
of a computer program stored in a computer readable memory, and a
specific manner in which components of an electronic device are
configured to cause that electronic device to operate. The various
blocks shown in FIGS. 4A-B may also be considered as a plurality of
coupled logic circuit elements constructed to carry out the
associated function(s), or specific result of strings of computer
program code stored in a memory.
[0093] Such blocks and the functions they represent are
non-limiting examples, and may be practiced in various components
such as integrated circuit chips and modules, and that the
exemplary embodiments of this invention may be realized in an
apparatus that is embodied as an integrated circuit. The integrated
circuit, or circuits, may comprise circuitry (as well as possibly
firmware) for embodying at least one or more of a data processor or
data processors, a digital signal processor or processors, baseband
circuitry and radio frequency circuitry that are configurable so as
to operate in accordance with the exemplary embodiments of this
invention.
[0094] Reference is now made to FIG. 5 for illustrating a
simplified block diagram of various electronic devices and
apparatus that are suitable for use in practicing the exemplary
embodiments of this invention. In FIG. 5 a wireless network
(serving cell 22, neighbor cell 26 or 28, NodeB if the serving and
neighbor cells are other than the NodeB, and RNC 24) is adapted for
communication over wireless links 21, 23 with an apparatus, such as
a mobile terminal or UE 20. The network may include a network
control element RNC 24, which provides connectivity with further
networks (e.g., a publicly switched telephone network PSTN and/or a
data communications network/Internet).
[0095] The UE 20 includes processing means such as at least one
data processor (DP) 20A, storing means such as at least one
computer-readable memory (MEM) 20B storing at least one computer
program (PROG) 20C, communicating means such as a transmitter TX
20D and a receiver RX 20E for bidirectional wireless communications
with the node B 22 via one or more antennas 20F. Also stored in the
MEM 20B at reference number 20G is the different procedures in case
the serving 22 and neighbor 26, 28 cells are the same or different
NodeB groups and the add/drop criteria which the UE 20 receives
from the serving cell 22, as detailed above.
[0096] The serving cell 22 also includes processing means such as
at least one data processor (DP) 22A, storing means such as at
least one computer-readable memory (MEM) 22B storing at least one
computer program (PROG) 22C, and communicating means such as a
transmitter TX 22D and a receiver RX 22E for bidirectional wireless
communications with the UE 20 via one or more antennas 22F. The
neighbor cell is functionally similar with blocks 27A, 27B, 27C,
27D and 27E, and both the serving cell 22 and the neighbor cell 26,
28 also store at 22G and 27G the different procedures and the
add/drop criteria. There is also a data and/or control path 25
coupling the neighbor cell 26, 28 and the serving cell 22 to the
RNC 24 via the NodeB (if neither cell is the NodeB itself).
[0097] Similarly, the RNC 24 includes processing means such as at
least one data processor (DP) 24A, storing means such as at least
one computer-readable memory (MEM) 24B storing at least one
computer program (PROG) 24C, and communicating means such as a
modem 24H for bidirectional communications with the cells 22, 26,
28 via the data/control path 25. While not particularly illustrated
for the UE 20 or cells 22, 26, 28, those devices are also assumed
to include as part of their wireless communicating means a modem
which may be inbuilt on an RF front end chip within those devices
20, 22, 26, 28 and which also carries the TX 20D/22D/27D and the RX
20E/22E/27E.
[0098] At least one of the PROGs 20C in the UE 20 is assumed to
include program instructions that, when executed by the associated
DP 20A, enable the device to operate in accordance with the
exemplary embodiments of this invention, as will be discussed below
in greater detail. The cells 22, 26, 28 and RNC 24 may also have
software to implement certain aspects of these teachings for
processing and signaling as detailed above. In these regards the
exemplary embodiments of this invention may be implemented at least
in part by computer software stored on the MEM 20B, 22B, 27B which
is executable by the DP 20A of the UE 20 and/or by the DP 22A/27A
of the cells 22, 26, 28, or by hardware, or by a combination of
tangibly stored software and hardware (and tangibly stored
firmware). Electronic devices implementing these aspects of the
invention need not be the entire UE 20 or cell 22, 26, 28 or RNC
24, but exemplary embodiments may be implemented by one or more
components of same such as the above described tangibly stored
software, hardware, firmware and DP, or a system on a chip SOC or
an application specific integrated circuit ASIC or a digital signal
processor DSP.
[0099] In general, the various embodiments of the UE 20 can
include, but are not limited to: cellular telephones; data cards,
USB dongles, personal portable digital devices having wireless
communication capabilities including but not limited to
laptop/palmtop/tablet computers, digital cameras and music devices,
and Internet appliances.
[0100] Various embodiments of the computer readable MEMs 20B and
22B include any data storage technology type which is suitable to
the local technical environment, including but not limited to
semiconductor based memory devices, magnetic memory devices and
systems, optical memory devices and systems, fixed memory,
removable memory, disc memory, flash memory, DRAM, SRAM, EEPROM and
the like. Various embodiments of the DPs 20A/22A/27A/24A include
but are not limited to general purpose computers, special purpose
computers, microprocessors, digital signal processors (DSPs) and
multi-core processors.
[0101] Various modifications and adaptations to the foregoing
exemplary embodiments of this invention may become apparent to
those skilled in the relevant arts in view of the foregoing
description. While the exemplary embodiments have been described
above in the context of the UTRAN system, it should be appreciated
that the exemplary embodiments of this invention are not limited
for use with only this one particular type of wireless
communication system, and that they may be used to advantage in
other wireless communication systems such as for example GERAN,
E-UTRAN and others.
[0102] Further, the various names used in the above description
(e.g., CELL-FACH state, names of the various channels) are not
intended to be limiting in any respect, as different radio
technologies may use different terms for similar concepts. Some of
the various features of the above non-limiting embodiments may be
used to advantage without the corresponding use of other described
features. The foregoing description should therefore be considered
as merely illustrative of the principles, teachings and exemplary
embodiments of this invention, and not in limitation thereof.
* * * * *